Automatic machine-rifle.



LM. BROWNING.

AUTOMATIC MACHINE RIFLE.

APPLICATION FILED AUG.I| 19H.

Patented Feb. 4, 1919.

,Il IJIIIJIIIIIII IIIIII II lLNIIIrIIIIII: I I I I I x JOHN' M. BROWNING, 0F OGDEN, UTAH.

AUTOMATIC MACHINE-RIFLE.

Specification of Letters Patent.

Patented Fen/1, 1919.

Application led August 1, 1917. Serial No. 183,841.

VTo all 'whom it may concern:

Be it known that I, J oHN M. BRowNING, a citizen of the United States, residing in Ogden, in the county of Weber and State of Utah, have invented certain new and useful Improvements in Automatic-Machine-Riiles, of which the following is a specification, reference being had to the accompanying drawings, forming a part hereof.

The invention generally relates to machine rifles in which all operations of the and yet most durable,

mechanism, except that of the trigger, are automatically effected, and in which the form and the weight of the rifle adapt -it for using highly charged military ammunition, the shooter either lyingl prone upon the ground, or standing erect with only his hands and shoulder supporting the rilie.

The invention specially relates to novel improvements in gas-operated machine rifles in which a vent in the barrel leads to a gas cylinder kept below the vent by a band allowing the barrel to expand lengthwise. The forward end of the cylinder is closed, the rear end fixed in the breech casing. The

gas cylinder has a series of radial openings Y through which the powder gases escape after having exerted pressure upon theI gas piston in the cylinder. Some distance forward of the breech Vcasing the gas cylinder carries a block from the bottom of which a bar extends to the breech casing where it is fixed. The main object of the invention is to provide a machine rifle adapted to lire highly charged military cartridges, but so light in weight `as to allow of one person carrying it and firing it from the shoulder,

This object is attained by providing novel constructions for transforming the necessarily very rapid movements of members of the mechanism at certain points not reducing the tionof the arm, ing same. Heretofore, class firing having a. high rate of speed of operation, though heavier and apparently stronger, have been' injured or wracked to pieces by a comparatively short use. In the accompanying drawings: Figure 1 represents a left hand side but; rather at will' increasmost firearms of this vation of the machine rilie, with portions broken away.

2 represents a top view of the central Fig.

of the machine rie.

portion of their path, yet thereby i rate of speed of the opera-Y highly charged cartridges andele- - from below and the butt stock G.'

Fig. 4 represents a similar view to Fig. 3, Y. but with the breech block unlocked and moved to its rearmost position.

Fig. 5 represents a front view of a vertical transverse section through the receiver at a place somewhat forward of the front end of Fig. 4, and with the parts in thesame position as in Fig. 4, looking rearward; the magazine being removed, and the vmagazine guide, shell ejector, the magazine latch and the 'breech block shown in front view.

Fig. 6 represents a vertical transverse section inthe line 6-6 of Fig. 4, through the receiver and trigger plate, and the parts therein, seen from the rear, the Sear, the Sear shifting button or firing controller and the handle andits arbor being represented as not in section.

' Fig. 7 represents a top view of the trigger plate detached, with the parts contained therein.

Fig. 8 represents a. vertical longitudinal section of the trigger plate with' the parts therein. v

Fig. 9 represents a top view of the cartridge magazine detached.

Fig. 10 represents an upper the cartridge so as to exposetoview the magazine follower, a part of the follower spring, and a number of cartridges resting upon said follower', seen from the rear.

Fig. 11 reprV nts a portion of the cartridge magazine, an upper part of which is in section, so as to expose to view some of the cartridges therein, seen from th'e front.

Fig. 12 represents in the three positions, X, Y, Z, the new rotary shifter T andthe portion `of positive springrsupported stop t1 for same.

vSimilar Vletters refer, to similar parts throughout the several views.

The machine riiie represented 1n the drawings comprises the following main parts: the

breech casing A, the barrel B secured tothe breech casing, the breech-,block C and the locking .brace D; the trigger plate E closin `at the bottom the rear portion ofthe breec cartridge magazine F inserted Vinto the breech casing and locked there inA front of casing, the

the trigger plate,

magazine partly in section, l

The barrel B has a vent. Below. the venteY is the gas cylinder H, its front end closed, its'rear end fastened in the breech casing. Some distance forward of the breech casing the cylinder H takes the form of a cubical block z, from the under side of which a flat uide bar extends into the breech casing-and 1s locked therein, by a transverse pin h1. In the cylinder the piston head I is fitted from which the piston rod L of slightly vSmaller diameter extends rearward through lthe cylinder H and the cubical block h. In

I -rear of the block the pistn rod L carries a 'crosshead from which a lug depends into a spring and piston clearly shown in Fig. 3,

groove in the guide bar I-I, and frem thecrosshead rearward it formsthe action slide, being divided `in two side bars separated by 'an open space of suiiicient width for the passageof the cartridge magazine therethrough; at the rear end of the actlon l slide L- the twov sid/esbars vare united by an integralcrossbar Z. The breech casingbelow the barrel has'a wide opening for the entran'ceof the rear end ofthe action slide and two internal grooves in which the side bars of the -slide are guided. After the crossbar Z has passed into the casing through said opening a plate is removably -itted in the casing below the barrel. from which a short ,guide rod Il: extends some distance in front of the breech casing.

Slightly in rear of the vent the cylinder H has a series of holes through which the 1n which the cylindrical tube g containing the reaction spring K and the piston p, carries'on its its exterior a strong annular collar g1 upon the outside of which is attached by a screw thread the rear endof a second larger'tube 7', which extends forward somewhat beyond the innersmaller tube g; the interiorly shouldered front end ofthe larger tube 1 is'closed by a shouldered annular buffer plate s which projects forwardly beyond the end of Ithe tube 1 and is rearwardly mov able therein. Through the central opening in the buffer plate .sthe piston p -of the reaction spring may freely slide, and the space between the collar 'on the smaller tube and the buffer plate, s is packed with annular disks 81 o r coils of a resilient material. The rear end of the smaller tube q is closed by an adjustable-screw plug p1- which carries centrally upon its forward face -a guide pin for the rear end .of the reaction spring K.

From the piston p a rod o extends forward powder gases may escape after exeliingtheir pressure upon the piston I. Either on the piston rod L and between it and the cylinder H the usualreaction spring K is V`located, its forward endbearin (against. ,the

pistonV head I its rear'end agamsttheface of the block/.h of the cylinder; onthepi'ston rod Ir'inayy be Vtubular and contain the forward end of'the reaction springK the rear end of which is'in that case supported bythe guideA rd Ic and plate fastened in the breech casing. e V

It is obvious that when the reaction spring is fully compressed the rearward movement of the pistonI un er the pressure of the'gases, the reaction springK .not only serves to return the pistonand action slide forward, but it also serves to cushion the action slide by absorbing any excess of energy.

This arrangement of the gas vent, cylin- -der 4and piston, with the reaction'sprin'g on the piston rod or 'in the piston'rod, located alongside the barrel for the automatic opleration of the action slide, is a well known e one and needs no further illustration or description.

In Fig. 3 an alternate of this arrangei ment is shown in which the tube containing the reaction spring and the piston actuate thereby are located in rear of the breech mechanism. The main difference in this arrangement from the former one is that a 'recoil residing in the action slide L:at` the limit of. its rearward movement, and to assist the reaction spring K in returningtlie action slide and the breech blockforward; but by screwing the inner smaller tube g, and the collarll1 thereon more or 4less into the lar 'er tube r, the de ee of resiliency of 115 the bu er may Abe readily adjusted by :the degree of compression of the' packing 81, and thereby the starting of the return movement of the action slide and the breech block may be made quicker or slower, so as to cause 120 a more rapid or a slower rate of automatic firing of the rifle.v 4

The rear of the barrel is closed by the breech Ablock C fitted tov reciprocate in the breech casing A guided there vertically7 by 125 the top of ythe. casing and two `longitudinal ribs a. a which project inward from the sides of the casing. See lig. '5.- The breech block C forits support'in the forward-firing position carries a pivotally attached locking '130 brace D, the rear of which is adapted to be row parallel top openings at both ends of the magazine, the over-hanging edges of the sides form a wide curved opening.Y The front and rear walls have each a recess which permits the lower portion of `the breech block to slide lengthwise through the magazine. The rear. portion of the cartridge chamber in the barrel is inwardly chamfered -to form at the bottom and both sides an upward and inward conical incline leading into the cartridge chamber.

When the breech block moves forward from its rearmost position, its lower portion engages the topmost cartridge in the magazine and forces it forward. As the bullet encounters-the chamfer, in its continued forward movement, its point is forced inward lcolumn as with those in the as the chamfer 'in the barrel will guide the locking brace 1s and upward, the narrow forward' opening in lthe toiof the magazine permitting the small bu et -to pass out of the magazine.

By this simultaneous forward, upward and inward movement the cartridge is caused to incline in its'` entire length, and, as during this movement the large portion of the cartridge has reached the wide-central opening in the top of the magazine, it can leave the same and the breech block can fully force the cartridge into the chamber of the barrel. This insertion directly vfrom the wide square box magazine into the. barrel is effected as readily with the cartridges in the right hand leftvhand one,

rising cartridges from either side into the chamber.

. The breech block is provided with the.

firing pin N, shell extractor O, and has in its bottom a central groove for the shell ejector P. The firing pin ANatts rear end has an enlarged head n and the locking brace has in its lunder side a central longitudinal groove` forclearing the body of the iiring pin. Near its rear end the locking brace has an upwardly extending hole o' connected with the groove, for the head'nl of the firing pin, the forward edges of this hole c acting like a cam upon thek head n, so that as the lowered the firing pin is ositively retracted to its rearmost position m which its firing oint is wthdrawninto the breech block, ihus making a positive safety device.

The locking tends downward brace below its rear end exand has a bossfd divided Y ered by t rearward, it thereby by a central recess -in which the link M is` attached by its upper pivot, the lower pivot of the link being attached tothe crossbar l ofthe action slide. w Y

At the place where the bottom of the locking brace and' the front face of its downward extension meet, a double cam of substantially quadrantal form is provided; said cam consists of an upper portion curving 'downward from the horizontal under side of the brace and of a .lower portion curving forward from the vertical face of the extension, both of these curved portions being connected. Y

By the first rearward movement of the action slide the locking brace is lowered to unlock the breech block and is stopped by the stop studs R, R, provided in the breech casing. As the brace is lowered, instead of it striking a violent blow upon the top of the stops R, R, the lower portion of the cam will engage the rear of the stops with a glancing blow. At the instant when the top of the lowered brace clears the inside ofthe breech casing, the cam transforms the downward movement of the brace into a longitudinal rearward one and thus prevents injury to brace or stops. In addition to the cam on the brace for preventing a violent blow upon the stops as just described, the link M is providedin rear of its upper pivot with a shoulder m, shown in Fig. 3 as eXtendiE-g nearly horizontally rearward from the li when the brace is inv the upper breech blocklocking 'osition. When the brace is lowe downward pull on it of the link as the same is drawn rearward by the action slide, the projecting shoulder m is turned upward and forward upon the upper link pin as a fulcrum, rear corner of the top of the brace has fully cleared the under surface of thebreech casing, the shoulder m, then nearly vertical is brought up against the rear .face of the brace, and as the link then draws the brace increases the action of the cam'in transmitti rearward movement to brace and breechnblock. Consequently, when the rapidly rearward moving action slide commences through the link to draw along the breech `block and brace, it finds these members already started in the rearward direction; therefore, any sudden strain upon the action slide, link, its pivots, bracez and breech block due to their inertia -is avoided and these parts -are therebyv saved' from injury to which they would be exposed were the movement lof the action slidev suddenly'transferred'to them while they stood the reciprocating members of the breech mechanism as well action slide must be= easily started,'t-hen moved at a greatly yincreased speed, and, finally, .the resulting and starts the :breech block rearward when4 the rounded upper rear corner of the locking brace can-.slide under the abutment on the receiver. '1 he s eed of the rearward movement of the actlon slide is then gradually diminished by the compression of the reac- -tion spring,

which aided by the buffer spring, finally stops the slide entirely and returns it forward.A

Durin this rearward movement thecenters of t e three pivot pins lie substantially in astraight line. inclming rearward and downward, but with the central pivot' slightly below this line to which position -therounded rear corner of the locking brace, when sliding forced the Acenter of the middleA pivot, as

hereinbefore described.

The momentum of the heavy breech' block .afterA rapid rearward movement .has been .imparted to it directly absorbe or diminished, so that during the rearward movement the breech l block actually pushes the brace, link and movement were still due to the -top of the brace.

slide rearward, and thereb prevents the middle .pivot from rising ,and7 t us keeps the top 'of the breech blockand llocking brace `from frictional lcontact with the inner surface ofthe fop of the receiver, a freedom which would the slide of the link and brace, as such draw- --ing instead ofv depressin 'would l'tend to pivot an thereby also theralse the middle During the ensuing forward movement, and up to the-point where the cam-of the brace strikes the studs R, R, the action slide,-

li'nk,.locking brace and breech block remain relatively: in the same position in which they are' shown in Fig'. 4, with the. center of the p1vot pin connecting the locking brace with the breech block and the center of the pivot pin connecting the link with the action slide in a stralght line inclining real ward and downward, but with the center of the middle pivot pin connecting the link with the brace below this line;

owder gases against the as under the abutment, has

the action slide, is not not result if the rearwarddrawing by the trigger plate E, andthe by this disposition and because again a push transmits the movement of the action slide to the link, brace and breech block, it keeps down the middle pivot pin and the brace and again presents frictional contact'of the same with the under side of the top of the breech casing, and thus greatly facilitates the forward closing movementof the breech block.

Rigidly attached to the crossbar l is the hammer or striker S. Its central portion projects upward-into the path of the firing .pm head n and on fthe last of the forward movement of the action slide, after the link` has raisedvthe brace D and thereby locked the breech block C .in the firing position, the projection of the hammer strikes upon the head nof the firing pin, and this percussion ignites the primer of the cartridge. During this forward movement of the action slide andthe transforming of this movement into the vertical one necessary to raise the locking brace, the reversed action of the link and that'of the upper portion of the cam of the brace on the stops R, R, .cushions the forward movement of the breech block so that the same will confine the cartridge in the chamber of the barrel without delivering a blow liable to injure the operating parts.

In the present embodiment of the important improvements the rearwardly moving action slide is stopped either by the combined reaction and cushion spring located below the barrel, or-by the combined action of the reaction spring K and of the separate cushioned buffer late` s in the 4butt stock by which the action slide is returned forward in its counter-recoil. If the riie is to'b'e fired with .reduced or with increased a speed by at will firing single shots each controlled by the trigger U, a device is provided for absorbing any excess ,of counter-recoil,

shown in Figs. `3, 4,7 and 8. Unless depressed by the operation of the trigger, which is mounted on a fixed pivot in in the trigger plateE, rthe rear end o the two armed scaru serves as asto for the action slide L,- byengaging a notc in the bottom of the inte al cross bar Z of t'he slide; the sear u is p lvoted above the trigger U and its pawl inthe separate slide e lengthwise movably mounted in a recess in the top of lslide e carries on a pin on its front a strong helical buffer sprm'g, g', the forward end of which rests againsta fixed point of the trigger plate E, while a horizontal slot in the slide e for the trigger pivot in is rpvided to allow this movement.v lhe 4bu er spring sorbs the blow of the counter-recoil and prevents injury to the rear end of the sear.

= Thepresent embodiment of theautomatic rifle as represented inFigsB, 4, 6, 7' and 8, is providedlwith a laterally slidin shifter T mounted in a transverse seat in t e -trig er plate above the upper rear end of the trigg thus abposition in which single shots ma The rear end of the Sear u standing ger U, which 4serves for at will changing the ring mechanism from the position in -which single shots may be fired under theV control of the trigger, to the position in which volleys of shots may be'ired and controlled by the operation and retention of the trigger.

and its release and by the capacity of the magazine, or to the safety position where depth, which may at will be brought above the rear end of the trigger b thelaterally slidin movement of the shi er.

In ig. 6 the shifter T and the several steps in its under side are clearly shown, and above it a spring t, also shown in Fig. 8, and several notches to frictionally keep the shifter in any of its several positions.

In Fig. 4 the shifter T is shown in the be fired. in the notch of the action slide holds the latter in its rear position from which it 'will be released if the trigger is pulled.

In Fig. 3 the parts are also shown in the position for firing single shots, but thev trigger has been pulled so as to cause the seai to' release the action slide which has been returned forward. The pawl pivoted in the trigger 'has raised the forward end of the sear for releasing the slide L, and the pawl has then'been thrown with its upper end forward, beyond the front end of the sear, by striking the front face of a cross bar in the slide e, which face is inclined forward and upward; -by this arrangement the sear is released to again engage the notch in the action slide when the same is next thrown 'to the rear by the firing of a shot.

' In Fig. 8 the parts are shown adjusted for automatic firing, and the trigger is represented as having been pulled and retained `in its rear position,wvliereby the rear end of the sear u has been lowered entirely out of the path ofthe action slide by the trigger pawl raising the front end of the sear u, the pawl being kept in operative position by its rear end bearing against the shifter On firing, the action slide will be thrown to the rear, and, not being` retained by the sear, will be at once returned forward as long as cartridges for continued automatic firing are supplied.

In Fig. 12 is represented an improved or rotatory shifter T for changing the controlling mechanism from .the single shot position to the volley positipn, or to the locked position. As shown 1n the partial section the rotatory shifter consists in a strong pivot mounted and located in the trigger plate and provided with a series of peripheral recesses of varying depth, from which pivot a crank arm extends upward, which arm may be moved from the forward position X to the central position Y or to the rearward position Z, these three positions bein also clearly represented 1n a small, horizontal sectionshown in Fig. 12. There is no obstacle to change the shifter from the forward position X to the central position- Y, but when arrived at the central position Y a small horizontal stop pin t1 projects fromxthe side of the casing and positively prevents the shifter arm from being rotated to the rearward osition Z until the stop t1 is pushed inwar ,which cannot be. done except by intentional pressure upon the end of the stop t1. After the stop t1 has been pushed out of the path of the shifter arm T and the same has been turned to the rear position the-shifter may at any time be again moved from its rearmost locking position to the volley firing central `position and from there to the Single shot firing forward position by simple pressure against the upper part of the shifter arm in the forward direction, because the for ward edge of the shifter arm is slanting inward and rearward so as to automatically press the stop pin t1 out of its path when the shifter arm is moved in the forward direction; but the arm being square or vertical to the side of the casing, when it encounters the stop pin in its rearward movement the stop will positively holdl it until the .sto itself 1s removed out of the shifters lpat which cannot be done accidentally, ut deliberate and intentional action of the operator. By this means the shifter may be readily moved for bringin into action the volley firing instead of 't e single firing,

but cannot be accidentally moved too far and, therefore, stop all firing' at a time when it is desired to shoot a number of shots with the greatest possible rapidity by holding the trigger. It would be a fatal fault if the shifter arm were unintentionally moved too far to the rear just at the ltime when the operator wanted the most ra id fire and maximum number of shots. T is accident is positively prevented by the stop t1 described.

I claim:A i y 1. In an automatic firearm, the combination of a breech casing, a barrel supported thereby, a reciprocating breech block mounted in said breech casing for reciprocation in a right line foropenng and closing said barrel, a locking brace pivoted to said breech block, an abutment on the breech casing for engaging the rear face of said locking brace, a reciprocating gas-operated action slide located below said locking brace, a gas-cylinder and piston for operating said action slide, a link pivoted to the rear end of said locking brace and to said action rear edge of the shifter' the provision of,

ioo only by the isc slide, and a shoulder on said link for engagement with the rear face of said lock.

ing brace during vthe reciprocation of-said breech block.

2. In an automatic firearm, the combination of a breech casing, a barrel supported thereby, a reciprocating breech block mounted in said breech casing for reciprocation in a right line for opening and closing said barrel, a locking,J brace pivoted to said breech block and having a rearlocking face,

Aan abutment on the breech casing having a lockin surface extending to the lower surface of the upper portion of the breech casing for engaging the rear locking face of said brace and preventing any rearward -movement of said breech block until the block are drawn rearward, a cam surface upon the underside 'of said locking brace, and stationary means so located upon said -breech casing as to be engaged by said cam surface after the rear end of said locking brace Ihas been pulled downward suiiiciently to bring its locking face below the lower edge of said abutment, whereby the downward movement of said locking brace is stopped without violent blows and said breech block is started rearward without sudden strains vupon the parts connecting it with the action slide. l

3'. In an automatic firearm, the combination of a breech casing, a barrelsupported thereby, a reciprocating-breech block mounted in said breech casing for reciprocating in a right line for opening and closing said barrel, a locking brace pivoted to said breech ".block, an abutment on the breech casing for engaging the rear face of said locking brace, a reciprocating action slide located below said locking brace, a gas cylinder and piston for operating said action slide in one direcfor operating said action slide in vthe ot er direction, a link between said brace and said action slide whereby when said action slide moves rearward, the rear end of said brace is first tion, a reaction spring pulledl downward and said brace and the breech block are thereafter drawn rearward,

and when said action slide moves forward said brace and said breech block are forced forward and the'rear end of said brace is I' thereafterf forced upward, a cam surface upon the underside of said locking brace,

' v and stationary means upon saidbreech casing engaged by'lsaid .cam surface when the brace, n

,forward movement of said locking brace are stopped without violent blows.

4. In an automatic firearm, the combination of a breech casing, a barrel supported thereby, a reciprocating breech block mounted in said breech casing for reciprocating in a right'lineior opening and closing said barrel, a locking brace'pivoted to said breech block, an abutment on the breech casing for engagingthe rear faceof said locking brace, a reciprocating action slide located below said locking brace, a gas cylinder and piston for operating said action slide in one direction, a reaction spring for operating said action slide in the other direction, a link connection between the said brace and said action slide, a cam surface upon the under side of said locking brace substantially quadrantal in form, and correspondingly shaped stationary means upon said breech casing engaged by the lower portion of saidv v5'. In an automatic firearm, `the combinas tion of a breech casing, a barrel supported thereby, a reciprocating breech block mounted in said breech casing for reciprocating in a right line for opening and closing sai-d barrel, aA. locking brace pivoted to said breech block, an abutment on the breech casing` for engaging the rear face of said lockin brace, a reciprocating action slide locateg inder and piston for operating said action Slide in one direction, a reaction spring for operatingv said action slide in the other direction, a nk connection between -the said brace and said action slide, a cam sur-V face upon the under side of said. locking brace comprising two connected curved portions, and correspondingly curved stationary means upon said breech casing engaged by one of said curved portions when `the rear end of said locking brace is pulled downward and engaged by the other of said curved portions when said locking brace is forced forward, whereby the downward and the forward Amovements of said locking brace are stopped without violent blows.

6. Inan automatic firearm, the combinationv of a breech casing, a barrel supported "thereby, a reciprocating breech block mounted in said breech casing for reciprocation in .a right line foropenlng and closing said barrel, a locking brace pivoted to said breech block.. an labutment on .the breech casingfor engaging the rear face of said locking brace,

below said locking brace, a gas cyl-A lll upon the under side of said locking brace,

stationary means upon said breech casing enc gaged by said cam surface when the rear end -of said locking brace is pulled downward or pushed upward, and a shoulder on said link for engagement with the rear face o said locking brace during the reciprocation of said breech block.

7. In an automatic rearm, the combination of a breech casing, a barrel supported thereby, a reciprocating breech block mounted in said breech casing for reciprocation in a right line for opening and closing said barrel, a locking brace pivotedl to said breech block, an abutment on the breech casing for engaging the rear face of said lockin brace, a reciprocating gas-operated action side located below said locking brace, a gas cylinde'rand piston for operating said action slide, a link ivoted to said brace and to said action sllde, whereby when said action slide moves rearward the rear end of said locking brace is rst pulled downward and thereafter said brace and the breech block are drawn rearward, a shoulder on said link for engagement with the rear face of said locking brace with the center of the pivot pin connecting said link to said brace lying below a line joining the centers of the pivot pin connecting said brace to said breech block and the pivot pin connecting said link to said action slide, during reciprocation, a cam surface upon the under side of said locking brace, and stationarymea-ns upon said breech casing engaged by said cam surface when said breech block is being' moved forward to close said barrel, whereby the forward movement ot said locking brace and breech block is stopped without violent blows, and said locking brace is forced up- Ward, raising above sald line the center of said pivot pin connecting said locking brace to said link.

8. In an automatic rearm, the combination of a breech casing, a barrel supported thereby, a reciprocating' breech block mounted in said breech casing for reciprocation in a right line for opening and closing said barrel, a locking brace pivoted to said breech block, an abutment on the breech casing for engaging the rear face of said locking brace,

aA reciprocating gas-operated action slidel vvlocated below said locking brace, a gas cylinder andpston for operating said action slide, a link pivoted to said brace and to said action slide, whereby when sald action slide moves rearward the rear end of said locking brace 1s first pulled downward and thereafter said brace and 'the breech block are Vjiravvn rearward, a cam surface on the upper side of said locking brace co-acting with said abutment to depress the locking brace, a shoulder on said link for engagement with the rear face of said locking'brace with the center of the pivot pinconnecting said link to said brace lying below a line Joining the centers of the pivot pin connecting said brace to said breech block and the pivot pin connecting said link to said a'ction slide during reciprocation, a cam surface upon the f underside of Said locking brace, and stationa means upon said breech casing co-acting with s 'aid last mentioned cani surface when said lockin brace is pulled downward, and when said reech block is moved forward vto close said barrel. v-

9; In an automatic firearm, the combination of breech casing, a barrel supported thereby, a reciprocating breech block for opening and closing said barrel, a reciprocating as-operated action slide, a as cylinder an piston for operating sai slide, a

shoulder on said action slide, a trigger plate closing the bottom of said breech casing, a pivoted sear for engaging said shoulder on the action slide upon the forward movement of said action slide, a spring cushioned slide mounted in said trigger plate upon which said sear is pivoted, a trigger pivoted in said trigger plate for movement about its pivot only, a pawl pivoted on the trigger for tripping sald sear and thereafter releasing same, or for holding said sear in inoperative position where said sea'r will not engage the shoulder on said action slide, and means for varying the limit of movement of the trig er and pawl whereby the shot to volley firing.

10. In an automatic firearm, the combination of a breech casing, a barrelv supported thereby, a reciprocating breech block for opening and closing said barrel, a reciprocatinggas-operated action slide, a gas cylinder and piston for operating said slide, a shoulder on said action slide, a trigger plate closing the bottom of said breech casing, a pivoted sear for engaging said shoulder on the action slide upon the forward movement of said action slide, a spring cushioned slide mounted in said trlgger plate upon which said sear is pivoted, a trigger `pivoted in said trigger plate for movement about its pivot only, a pawl pivoted on the trigger for tripping said sear and thereafter releasing same, or for holding said sear in inoperative position where said sear will not engage the shoulder o n said action slide, 'a cam surface on said 'spring cushioned slide for engaging said pawl and disengaging it from said Sear, and

lso

- tion with breech mechanism, firing mechanism and mechanism` for controlling the firing, of a rotatory shifter for engaging the mechanism for controlling the firing, whereby the firing may at will be changed from single shot to volley. firing, or, whereby' the mechanism for controlling the firing may be locked against operation, an arm on said shifter for rotating'same, a removable stop in the path of saidI arm positively preventing movement of said shifter from volley firing position to locked position, but-yielding to permit movement of said shifterl from locked tion.

12. In an automatic firearm, the combination of a breech casing, a barrel supported thereby, a reciprocating breech block for opening and closing said barrel, a locking brace pivoted to. said breech block, an abutment on the breech casing for 'engaging the rear face of said lockingbrace, a reciprocating gas-operated action slide located below said locking brace, connections between said action slide and said locking brace whereby said locking brace is pulled,V downward when said action slide moves rearward, a firing pin mounted for reciprocation in said breechl block and having at its rear end an enlar ed head,- and a hole or recess extending into the lower portion of saidlocking brace and adapted to fit over said head, said hole having its forward wall slotted, the two edges of said slot engaging said head on each side of the firing pin andreposition to volley ring positracting the firing pin when the locking tion of a breech cas1ng,

brace is pulled downward and thereafter positively holding said firing pin retracted until said breech block has returned to closed position.- V y 13.` In an automatic firearm, the combinaa barrel supported thereby, a reciprocating -breech block for opening and closing said barrel, a locking brace pivoted to said breech block, an abutment on the breech casing for engaging the rear face of said locking brace, a`reciproeating gas-operated action slide located be` low sai locking brace, connections between said action slide and said locking brace whereby sa'id locking brace is pulled downward when said action slide moves rearward, a firing pin mounted for reciprocation in said breech block and having gt vits rear end an enlarged head, a central longitudinal groove in theunderside of said locking brace, terminating at its rear end in a wider recess or hole, whereby when said locking brace is pulled downward said groove accommodates the body of said firidly supported by said ing pin while the two ed es of said recess en age said head of the ring pin on each Sife thereof, positively retracting the ring pin and holding it retracted throughout the reciprocation .of the breech block.

14. In an automatic firearm, the combination of a breech casing, a barrel supported thereby, a reciprocating breech block for opening and closing said barrel, a locking brace pivoted to said breech block, an abutment on the breech casing for engaging the rear face of said locking brace, a reciprocating gas-operated action slide located below sald lockingbrace, connections between said action slide and said locking brace whereby said locking brace is pulled downward when said action slide moves rearward, a ring pin mounted for reciprocation in said breech block and having a projection on its rear end, a cam surface upon the underside of said locking brace for engaging said projection .and retracting said firing pin when the locln'ng brace is pulled downward and thereafter positiyely holding said firing pin retracted until said breech block has returned to `closed position, and a hammer rigidly mounted upon said action slide for striking said firing pin after the breech blo'ck has returned to closed position and said locking brace has been raised to release the firing pin and to lock the breech block.

15. In an automatic firearm, the combination of a breech casing, a barrel, a reciprocating breech mechanlsm for opening and closing said barrel, an annular buffer plate in rear of the breech mechanism against which said mechanism strikes at the end of its rearward movement, a tube in the forward end of which said buffer plate is mounted, means upon said tube engaging said bui-fer plate for preventing forward movement of said plate while permitting free rearward movement thereof, a plug for closing the rear end of said tube, a tube of smaller diameter extending through and rigplug and extending throu h the first mentioned tube and into said ufer plate, a reactionv spring contained within said tube of smaller diameter, a 'piston cooperating therewith, and connections from said piston to said breech mechamsm.y

16. Irian automatic firearm, thecombination of a breech casing, a barrel, areciproeating breech mechanism for opening and closing said barrel, lalguiular ufer plate in rear of the bree :mechanism against which said-mechanism strikes at the end of its rearward movementf'a tube in the forward end of. which said buffer pla'te is mounted, means upon-said tube engaglng said buffer plate forl preventing forward, `movement of isaid plate while permitting toward and from said buffer plate, apacking of resilient material extending from said buifer plate to said plug, a tube of smaller diameter extending through and rigidly supported by said plug and extending throligh the first mentioned tube and into said bu er plate, a reaction spring contained within said tube of smaller diameter, a piston coperating therewith, and connections from sald piston to said breech mechanism. v

17. In an automatic firearm, the combination of a breech casing, a barrel, a reciproeating breech Ymechanism for opening and Aclosing said barrel, an annular-buffer plate in rear of the breech mechanism against which said mechanism strikes at the end of its rearward movement, a tube in the forward endof which said buffer plate is mounted, means upon said tube engaging said bul'er plate for preventing forward movement of said plate While permitting free rearward movement thereof, a plug for elosin the rear end of said tube adjustable towar and from said buffer plate, a packing of resilient material extending from said buier plate to said plug, a tube of smaller diameter extending through and rigidly supported by said plug and extending throlilgh the first mentioned tube and into said bu er plate, a Ireaction spring contained `within said tube of smaller diameter, arpiston cooperating therewith, connections :Erom said plston to said breech mechanism, and a plug for i i n mentioned tube adjustable toward and Vfrom said piston.

Thls specification signed and witnessed this 27th day of July, A. D. 1917.

JOHN M. BROWNING.

In the presence of- C. J EHBE'rs, A. L. ULRICH.

closing the rear end of said last 

